Silver Nanoparticles–Chitosan Nanocomposites as Protective Coatings for Dental Remineralization Treatment: An In Vitro Study

Research with nanoparticles for the treatment and prevention of dental caries is of special interest given the high prevalence of the disease worldwide. Several studies support the use of nanoparticles associated with materials given their antimicrobial properties and potential demineralization reduction. This study aimed to evaluate the impact of the application of silver nanoparticles (AgNPs) and chitosan gel in combination with commercial fluoride varnish on the remineralization of dental enamel. Ninety-six tooth blocks were macroscopically evaluated via stereomicroscopy, ICDAS II, and laser fluorescence. Enamel blocks were subjected to artificial demineralization and divided into four exposure groups (24, 48, 120, and 168 h), and five different remineralizing agents were applied, namely, FV (fluoride varnish), FV + CG (fluoride varnish + chitosan gel), FV + AgNPs (fluoride varnish + AgNPs), FV + AgNPs + CG (fluoride varnish + AgNPs + chitosan gel), and AgNPs + CG (AgNPs + chitosan gel). Enamel surface changes were evaluated via laser fluorescence, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Laser fluorescence results obtained from demineralized blocks and subsequently exposed to remineralizing treatment indicate significant differences. After exposure to remineralizing agents, hydroxyapatite and modified apatite phases were identified mainly in the samples treated with FV + AgNPs + CG in the groups exposed for 24, 48, and 120 h. The FV + AgNPs + CG and AgNPs + CG indicate good performance in terms of the Ca/P ratio in in vitro demineralization compared to the group treated with fluorine varnish.